Commit 49c692b7 authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
Browse files

perf offcpu: Accept allowed sample types only 



As offcpu-time event is synthesized at the end, it could not get the
all the sample info.  Define OFFCPU_SAMPLE_TYPES for allowed ones and
mask out others in evsel__config() to prevent parse errors.

Because perf sample parsing assumes a specific ordering with the
sample types, setting unsupported one would make it fail to read
data like perf record -d/--data.

Fixes: edc41a10 ("perf record: Enable off-cpu analysis with BPF")
Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: http://lore.kernel.org/lkml/20220624231313.367909-3-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent d6838ec4

tools/perf/util/bpf_off_cpu.c

+6 −1
Original line number Diff line number Diff line
@@ -265,6 +265,12 @@ int off_cpu_write(struct perf_session *session) 


	sample_type = evsel->core.attr.sample_type;



	if (sample_type & ~OFFCPU_SAMPLE_TYPES) {

		pr_err("not supported sample type: %llx\n",

		       (unsigned long long)sample_type);

		return -1;

	}



	if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER)) {

		if (evsel->core.id)

			sid = evsel->core.id[0];
@@ -319,7 +325,6 @@ int off_cpu_write(struct perf_session *session) 
		}

		if (sample_type & PERF_SAMPLE_CGROUP)

			data.array[n++] = key.cgroup_id;

		/* TODO: handle more sample types */



		size = n * sizeof(u64);

		data.hdr.size = size;

tools/perf/util/evsel.c

+9 −0
Original line number Diff line number Diff line
@@ -48,6 +48,7 @@ 
#include "util.h"

#include "hashmap.h"

#include "pmu-hybrid.h"

#include "off_cpu.h"

#include "../perf-sys.h"

#include "util/parse-branch-options.h"

#include <internal/xyarray.h>
@@ -1102,6 +1103,11 @@ static void evsel__set_default_freq_period(struct record_opts *opts, 
	}

}



static bool evsel__is_offcpu_event(struct evsel *evsel)

{

	return evsel__is_bpf_output(evsel) && !strcmp(evsel->name, OFFCPU_EVENT);

}



/*

 * The enable_on_exec/disabled value strategy:

 *
@@ -1366,6 +1372,9 @@ void evsel__config(struct evsel *evsel, struct record_opts *opts, 
	 */

	if (evsel__is_dummy_event(evsel))

		evsel__reset_sample_bit(evsel, BRANCH_STACK);



	if (evsel__is_offcpu_event(evsel))

		evsel->core.attr.sample_type &= OFFCPU_SAMPLE_TYPES;

}



int evsel__set_filter(struct evsel *evsel, const char *filter)

tools/perf/util/off_cpu.h

+9 −0
Original line number Diff line number Diff line 
#ifndef PERF_UTIL_OFF_CPU_H

#define PERF_UTIL_OFF_CPU_H



#include <linux/perf_event.h>



struct evlist;

struct target;

struct perf_session;
@@ -8,6 +10,13 @@ struct record_opts; 


#define OFFCPU_EVENT  "offcpu-time"



#define OFFCPU_SAMPLE_TYPES  (PERF_SAMPLE_IDENTIFIER | PERF_SAMPLE_IP | \

			      PERF_SAMPLE_TID | PERF_SAMPLE_TIME | \

			      PERF_SAMPLE_ID | PERF_SAMPLE_CPU | \

			      PERF_SAMPLE_PERIOD | PERF_SAMPLE_CALLCHAIN | \

			      PERF_SAMPLE_CGROUP)





#ifdef HAVE_BPF_SKEL

int off_cpu_prepare(struct evlist *evlist, struct target *target,

		    struct record_opts *opts);